Arc-lamp electrode.



G. EGLY.

lARG LAMP BLEGTBODE.

APPLICATION FILED 00T. 22, 1909.

- l1,009,291.r y Ptented N0v.21,1j911.

Be .it known that I, Gaone EGLY, a sub' ,saone EGLY,orrnxrrowfma'fsiiaivg'cnmgng, 'AssIeNon fro snsannn a comrmnror BERLIN,GERMANY. p

ject of the German Emperor, and residing A at Treptow, near Berlin,Germany, have in-A consist of light emitting in vented certain new anduseful Improvements in Arc- Lamp Electrodes, of which the following is ac My invention re atesto arc lamp electrodes and a primary obect istopr'ovlde an eleetrodecontaining p ho-boric acid. be understood arcomelectrodes ents, such as compounds of the alkalis, alkaline earths andrare earths, together 'with carbon or carbonaceous material and abinder, the latter being sometimes of carbonaceous material such as taror sometimes of water glass.'

My invention has for its object by the addition of phospho-boric acid toimprove the electrode, not only in its rocess of manufact-ure but also1n its be avior under the action of the electric current, and also toimprove the qualitytand character of the arc and thelight emittedthereby.

Phospho-borlc Aacid has the composition BPO4 and is obtained b theaction ofboric acid on 'phosphoric aci For example, if pulverized boricacid be placed into concentrated phosphoric acid a treacly mass is-flrstly obtained in which boric acid and phosphoric acid are containedseparately one beside the other. If this viscous mass be evaporated todryness, an earthy, exceedingly highl refractory mass, phosphoboricacld, is obtained. The same product is also obtained when a mixture ofthe anhydrids of boric acid and phosphoric acid is heated to redness.

I may employ the phospho-boric acid either in its inished form, or inthe form of the mixture of anhydrids, or in the form .of an emulsion ofboric acid in concentrated phosphoric acid. In the two last cases thephospho-boric acid is -rst formed in the carbon mass or in the finishedelectrode.

vAbove all it causes very quiet burning and renders entirelynon-injurious any lmpurities which the carbon or tar employed in themanufacture ofthe electrodes contains. It is related in certainrespects'in its action to boric acid on the one hand and tophosphoricacid on the other hand, but iswithout the disadvantages of these. Forexample boric acid and borates, `which are well- "91x01y I' 'itirati-on..o-'fLtters?iraient.l Appumion mea october as, moa serial ivo.523,977. "l v -j ification. v

` 3. nnncfrnonns 'Patentel Nov. 21, 1911.

i l Aknown. .quite generally for steadying the arc, are veryreadily'fusible and favor under -certain circumstances the formation ofslag, whereas phospho-boric acid, on the contrary, 1s practicallynon-fusible. Further, both bor1c acid and phosphoric acid, when added bythemselves alone'to the carbon mass, act lvery unfavorably on thewaterlass employed for binding the carbon.' T ey cause the water-glassto stien and take from it its lubricity. If phospho-boric acid beemployed instead, the water-glass retains its good properties.Phospho-boric acid is consequently very particularly suitable as anadmixture for core masses which are to be Vworked up with water-glass.

Phospho-boric acid is distinguished from borates when used as anadmixture with rsalts of thealkalis, earth alkalis or rare "`earths\inthat it possesses the advantage of regulating vaporization and alsoconcentrates the arc and considerably increases the emission of light.

. A further advantage is afforded by phospho-boric acid as compared with.borates in that electrodes containing phospho-boric acid and providedwith light emitting substances burn both -with direct and also withalternating current with lamp tensionsof up tov45 and indeed 50 voltswithout the arc being ruptured, whereas when carbons' of the same kindcontaining borates are used the arc ruptures at about 35 voltsparticularly in the case of alternating current.

Part of one form of my lmproved arc lamp electrode is represented by wayof ex-v ample. in vertical sectional elevation in the accompanyingdrawing wherein a design nates the carbon shell surrounding the core bcontaining carbon, light emitting substances and phospho-boric acid.

By way of illustrative example of an electrode composition embodying myinvention I mention the following composition: fluorspar forty parts,carbon forty parts and phospho-boric acid three arts. These ingredientsare mixed in t e usual manner with as much water glass as .willlproducea moldable mass. v

I claim:

1. An arc lamp electrode containing phos- 3. An arc lamp electrodeconsisting of al s Q t 1,099,291

shell of carbon surrounding a. core composed name to this specificationin the presence of of a, mixture of carbon, light emitting subtwowitnesses. stances `and phospho-boric acid. l 4. An arc lamp electrodeconsisting of `a i 5 mixture of carbon, a light emitting sub- Witnesses:v

stance, phospho-boris vacid. and Water glass. HENRY HASPER,

' in testimony whereof I have signed my WoLDEm GEORG EGLY.`

